Adjustment for calibration of instrument



Jan. 15, 1963 v. s. THOMANDER 3,074,016

ADJUSTMENT FOR CALIBRATION OF INSTRUMENT Filed May 5. 1960 ,X \55 32 l 36 Fig.l. o lo\ 0 l2 0 3o 0 Fig.2.

WITNESSE$= INVENTOR GM Rg k w 26 Veron S. Thomonder DZZI'TOR EY United States Patent 3,074,016 ADJUSTMENT FOR CALIBRATIGN 0F INSTRUMENT Veron S. Thomander, Maplewood, N.J., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a

corporation of Pennsylvania Filed May 5, 1969, Ser. No. 27,034 Claims. (Cl. 324-147) This invention relates generally to iron vane instruments and more specificaly to a calibrating adjusting means for a book type repulsion iron vane instrument.

An object of this invention is to provide an improved means for calibrating iron vane instruments.

Another object is to provide a calibration adjustment which is easy to use and economical to manufacture.

Other objects will be apparent from the specification, and claims and from the drawings, in which:

FIGURE 1 is a top plan view of a portion of a book type repulsion iron vane instrument embodying the invention;

FIG. 2 is a view taken substantially along the line II-II of FIG. 1 and looking in the direction of the arrows;

FIG. 3 is an isometric projection of the portions of the instrument shown in FIG. 1;

FIG. 4 is a partial sectional view showing a part of the adjusting means; and

FIG. 5 is an elevational view of the adjustable fixed vane.

Referring to the drawings by characters of reference, the numeral 1 designates generally a supporting structure having a circular lower end wall 2, an enlarged upper end portion 4 and an elongated circular cylindrical intermediat: portion 6. A part of the portion 6 is removed to provide a longitudinally extending wedge shaped aperture 8 defined by a pair of walls 10 and 12 which extend substantially at right angles to each other.

A flanged spool 14 surrounds the portion 6 and carries a winding 16 which is adapted to be energized proportionally to the magnitude of the electrical quantity to be measured by the instrument in any well known manner. The winding or coil 16 causes magnetic flux to flow longitudinally through the aperture 8 to magnetically charge a pair of relatively movable vanes 18 and 20. The vane 18 is carried on a shaft 22 journaled at its lower end on a bearing member 24 carried on this lower end wall 2. The upper end of the shaft (not shown) may be suitably journaled on a bearing member (not shown) carried by the enlarged upper end portion 6. The manner in which the shaft is resiliently urged into the illustrated position with the vanes 18 and 20 in substantially parallel juxtaposition and in which rotation of the shaft actuates indicating apparatus to indicate the rotational position of the shaft is well known and may take any of a number of forms well known to those skilled in the art. Since these structural features do not form any part of the invention and the invention may be fully described without the showing thereof, such features have been omitted to s'mplify the disclosure.

Because of the difficulty of manufacturing instruments whih have absolutely identical characteristics due to inherent differences in the materials used and other manu facturing tolerances which affect the relationship between the rotative position of the shaft 22 and the current flow through the coil 16, it is desirable to individually calibrate each instrument to compensate for the individual differences between different instruments so that it becomes unnecessary to custom make each indicium. In order to individually calibrate each individual instrument so that it will agree with the prepared indicia, I provide for adjustably supporting the fixed vane 20 in a manner suitable for easy adjustment, to accomplish calibration.

As illustrated (FIG. 1) the normal deenergized position of the movable vane 18 is in a plane spaced from but substantially parallel to the fixed vane 20 which seats against the wall 12. In accordance with my invention, the fixed vane 20 is provided at its lower edge with a V-shaped projection 26 which seats in a larger V-shaped depression 28 to provide a pivot point about which the vane 20 may be rocked. Both the end of the fixed vane and the depression seat may be round or some other shape to provide a center of rotation.

In order to conveniently rock the vane 20 in small increments, the upper edge thereof is serrated as at 30 and the adjacent portion of the supporting structure 1 is provided with a recess 32 having spaced side wall portions 34 and 36. Any suitable tool such as an ordinary screw driver (not shown) may be inserted into the recess 32 and the serrations 30 and by a slight rotative movement of the tool, the vane 20 may be rocked about its pivot.

Maximum torque is applied to the shaft 22 when the vanes 18 and 20 are in exact juxtaposition. Movement of vane 20 out of position reduces the repelling force between the vanes 18 and 20 for any given excitation of the winding 16. The wall 12 is located so that the vane 20 which seats thereagainst lies in a plane which is parallel to the plane of the radially exending vane 18 when it is in the illustrated position. The wall is offset with respect to the radial plane such that when the vane 20 is rocked toward the wall 10 the upper end of vane 20 barely misses as it moves past the shaft 22. Since it is desirable to keep the spool diameter as small as possible commensurate with the size of the vanes 18 and 2'8, the vane 20 is preferably arranged to be rocked from the illustrated aligned position of maximum torque on shaft 22 toward the wall 10 to decrease the repelling force between the vanes 18 and 20 and conversely.

The instrument is calibrated (vane 20 placed in its adjusted position) with a fixed value of current in the coil 16. A clamp device 35 is provided to clamp the vane 20 in its adjusted position. The device 35, as best illustrated in FIG. 4, comprises an inverted channel or clamping member 37 having downwardly facing side flanges, one of which engages the vane 21} and the other of which rides on a cam surface 38 formed in the bottom wall of the recess 32. A screw 40 which is screw-threadedly attached to the bottom wall of the recess 32 may be released to permit the channel member 37 to slide along the cam surface 38 to release the vane 20- so that the vane 20 may be adjusted inwardly or outwardly as the case may be to cause the pointer (not shown, which is actuated by the shaft 22, to assume its correct position with respect to the indicia (not shown). Thereafter the screw 41) may be tightened to draw the channel member 37 toward the bottom wall of the recess 32 causing the member 3'7 to follow the cam surface 38 thereby clamping the vane 20 against the wall 12 in its adjacent position. The screw 40 and clamping member 37 provide a securing apparatus cooperable with the cam surface 38 to clamp the vane 20 against the wall 12.

If greater adjustment is necessary a plurality of notches similar to the notch 28 might be provided or if desired, a slot could be provided instead of individual depressions or notches.

What is claimed and is desired to be secured by United States Letters Patent is as follows:

1. In an electrical measuring instrument, a supporting member having an elongated portion, said portion having an elongated chamber provided with a side wall, a rotatable shaft extending longitudinally of said chamber, a a first plate-like magnetic material vane carried by said shaft and rotatable with said shaft, said wall extending in a plane displaced from and substantially parallel to said first vane at one rotative position of said shaft, a second plate-like magnetic material vane positioned against said wall, means pivotally supporting said second vane in said chamber, said means including a recess in said supporting member and a projection on said vane which projects into said recess, and clamping means for securing said second vane against said wall in its adjusted position in said chamber, said clamping means including a cam surface on said supporting member and a substantially U-shaped member having a base portion and outturned side portions, said U-shaped member overlying an edge of said second vane with one of its said side portions engageable with said second vane and the other of its said side portions engaging said cam surface, said clamping means further including a fastening device cooperable with said base portion to force said other side portion along said cam surface to clamp said second vane against said chamber side wall.

2. In an electrical measuring instrument, a supporting member having an elongated portion, said portion having an elongated chamber provided with a side wall, a rotatable shaft extending longitudinally of said chamber, a first plate-like magnetic material vane carried by said shaft and rotatable with said shaft, said wall extending in a plane displaced from and substantially parallel to said first vane at one rotative position of said shfit, a second plate-like magnetic material vane positioned against said wall, means pivotally supporting said second vane in said chamber, said means including a recess in said supporting member and a projection on said vane which projects into said recess, said second vane having a serrated portion, said supporting member having a recess with spaced side walls adjacent said serrated portion, and clamping means for securing said second vane against said wall in its adjusted position in said chamber, said clamping means including a cam surface on said supporting member and a substantially U-shaped member having a base portion and outturned side portions, said U-shaped member overlying an edge of said second vane with one of its said side portions engageable with said second vane and the other of its said side portions engaging said cam surface, said clamping means further including a fastening de vice cooperable with said base portion to force said other side portion along said cam surface to clamp said second vane against said chamber side Wall.

3. In a magnetic vane type measuring instrument, a supporting structure provided with first and second end walls, said structure having a protruding cylindrical portion extending outwardly of said first end wall, said cylindrical portion being provided with a chamber opening outwardly through said second end wall, a shaft extending longitudinally of said chamber, means securing said shaft for rotational movement about its longitudinal axis, a first magnetic material vane in said chamber and carried by and extending outwardly from said shaft, said cylindrical portion having an end wall spaced from said first end wall and defining an end surface of said chamber, said cylindrical portion having a side wall intersecting said end surface and defining a side wall surface spaced from and parallel to said vane at one rotative position thereof, said end surface being provided with a recess adjacent the intersection of said surfaces, a movable part including a second magnetic material vane, said part being positioned to locate said second vane in parallel relation to said side wall surface, said part including a projection fulcrumed in said recess, said supporting structure being provided with a cam surface spaced from said side wall surface at a portion thereof remote from said end surface, a clamping member including a cam follower member engageable with said cam surface and d a portion engageable with said part, a clamping device carried by said supporting structure and engageable with said follower member to move said follower member along said cam surface to clamp said part in an adjusted position against said side wall surface, and a coil surrounding said chamber for magnetizing said vanes.

4. In a magnetic vane type measuring instrument, a supporting structure provided with a first and second end walls, said structure having a protruding cylindrical portion extending outwardly of said first end wallfsaid cylindrical portion being provided with a chamber opening outwardly through said second end wall, a shaft extending longitudinally of said chamber, means securing said shaft for rotational movement about its longitudinal axis, a first magnetic material vane in said chamber and carried by and extending outwardly from said shaf said cylindrical portion having an end wall spaced from said first end wall and defining an end surface of said chamber, said cylindrical portion having a side wall intersecting said end surface and defining a side wall surface spaced from and parallel to said vane at one rotative position thereof, said end surface being provided with a recess adjacent the intersection of said surfaces, a second magnetic material vane positioned in juxtaposition with said side wall surface, said second vane being provided with a wedge-shaped projection extending from one edge portion thereof seating in said recess, said supporting structure being provided with a recess opening outwardly through said second end wall and through said side wall surface, said recess having spaced side walls and a bottom wall, said second vane being serrated at its edge portion opposite to its said one'edge portion and adjacent said side walls of said recess, a portion of said bottom wall of said recess spaced from saiduside wall surface forming a cam surface extending at an acute angle relative to said side wall surface, a U-shaped clamp having a base portion and spaced side portions, one of said side portions engaging said second vane and the other of said side portions engaging said cam surface, a fastening device cooperable with said base portions to force said other side portions along said cam surface to clamp said second vane against said side wall surface, and a coil surrounding said chamber for magnetizing said vanes.

5. In an electrical instrument, a supporting member having a chamber provided with a wall, a first plate-like magnetic material vane, means rotatably supporting said vane in said chamber for bodily movement of said vane toward and away from said wall and having a rotative position in which said vane substantially overlies said wall, a second plate-like magnetic material vane positioned in said chamber and against said wall intermediate said first vane and said wall with said vanes in overlapping relationship, means pivotally suporting said second vane for movement in a plane parallel to said wall to vary the magnitude of overlap of said vanes, said means for pivotally supporting said second vane including first and second elements, a first of said elements being carried by said supporting member adjacent said wall, a second of said elements being carried by said second vane, one of said elements comprising a recess, the other of said elements comprising a projection projecting into said recess, and clamping means for securing said second vane against said wall in its adjusted position in said chamber, said clamping means including a cam surface and securing apparatus, said securing apparatus being cooperable with said cam surface to clamp said second vane against said wall.

References Cited in the file of this patent UNITED STATES PATENTS 

1. IN AN ELECTRICAL MEASURING INSTRUMENT, A SUPPORTING MEMBER HAVING AN ELONGATED PORTION, SAID PORTION HAVING AN ELONGATED CHAMBER PROVIDED WITH A SIDE WALL, A ROTATABLE SHAFT EXTENDING LONGITUDINALLY OF SAID CHAMBER, A A FIRST PLATE-LIKE MAGNETIC MATERIAL VANE CARRIED BY SAID SHAFT AND ROTATABLE WITH SAID SHAFT, SAID WALL EXTENDING IN A PLANE DISPLACED FROM AND SUBSTANTIALLY PARALLEL TO SAID FIRST VANE AT ONE ROTATIVE POSITION OF SAID SHAFT, A SECOND PLATE-LIKE MAGNETIC MATERIAL VANE POSITIONED AGAINST SAID WALL, MEANS PIVOTALLY SUPPORTING SAID SECOND VANE IN SAID CHAMBER, SAID MEANS INCLUDING A RECESS IN SAID SUPPORTING MEMBER AND A PROJECTION ON SAID VANE WHICH PROJECTS INTO SAID RECESS, AND CLAMPING MEANS FOR SECURING SAID SECOND VANE AGAINST SAID WALL IN ITS ADJUSTED POSITION IN SAID CHAMBER, SAID CLAMPING MEANS INCLUDING A CAM SURFACE ON SAID SUPPORTING MEMBER AND A SUBSTANTIALLY U-SHAPED MEMBER HAVING A BASE PORTION AND OUTTURNED SIDE PORTIONS, SAID U-SHAPED MEMBER OVERLYING AN EDGE OF SAID SECOND VANE WITH ONE OF ITS SAID SIDE PORTIONS ENGAGEABLE WITH SAID SECOND VANE AND THE OTHER OF ITS SAID SIDE PORTIONS ENGAGING SAID CAM SURFACE, SAID CLAMPING MEANS FURTHER INCLUDING A FASTENING DEVICE COOPERABLE WITH SAID BASE PORTION TO FORCE SAID OTHER SIDE PORTION ALONG SAID CAM SURFACE TO CLAMP SAID SECOND VANE AGAINST SAID CHAMBER SIDE WALL. 